When the battery in your phone isn't good enough, there's a plethora of external batteries available to pick up the slack. The ReVIVE ReStore Q10x is a 10,000mAh unit that usually costs about $35, but it's on sale at just $19.99 for the next few days. It's available with Amazon Prime shipping too.

Most portable external batteries make it easy to charge up a phone or tablet when your power runs low, but what about a computer? The ChargeAll can do both, and it has really excellent reviews on Amazon. The only problem is the price, but TouchOfModern has the ChargeAll heavily discounted if you don't mind waiting.

You can't get something for nothing, but in this case you can get pretty close. Power Skin has a killer Cyber Monday promotion with its PoP'n selling for just a penny. You still have to pay shipping, but that's only $8 for basic US delivery. You're probably wondering what a PoP'n battery is. Well, it's kind of weird.

Even the best of us have miscalculated and run low on battery before heading to an outlet, but that's what external battery packs are for. These devices pop up on sale from time to time, and today there's a good deal on the Poweradd Pilot X5 with a 16,000mAh capacity. The price usually hovers around $40, but you can score one for $24.99 with Prime shipping using the coupon code below.

There may not always be a power outlet nearby when you need one, so perhaps a giant external battery is something you should consider. In fact, there's a particularly massive battery from EC Technology on sale through Amazon right now. 22,400mAh of power for just $34.99.

This device is usually priced between $50 and $55, so this is a solid deal. It has two USB ports (up to 2.1A) and an LED flashlight for good measure.

Now that everyone seems to be carrying around smartwatches, Bluetooth headphones, and various other bits of electronic detritus, we need ways to keep them charged up when they inevitably die before the end of a long day. Samsung wants your Galaxy phone or tablet to be the backup battery for other stuff, like a Gear watch, via the brand new Power Sharing Cable. It's a little double-sided MicroUSB cable that allows one gadget to charge another, without any AC adapter or portable battery pack.

Technology in general and mobile tech in particular is on a rapid march forward, but there's a bottleneck that's holding it back: batteries. For years lithium-ion batteries have been the best option for storing energy pound-for-pound, but they've hit a wall - now we can only get bigger batteries or make our gadgets more efficient. A team of researchers at Stanford University have created what they call the "holy grail" of battery technology, a battery with a stable lithium anode.

Anker makes solid external batteries, and there's a nice deal on one of the larger ones over at Amazon right now. The Anker Astro E3 with 10,000mAh of juice can be yours for $25.99. This unit has a retail price of $80, but of course, you're never going to pay that. It usually bounces around $40, so this is still a good deal.

It seems like there are just never enough electrons in your phone, right? With just a few thousand milliampere-hour, it can be easy to drain your device before there's an outlet handy, so it's a good thing portable battery packs exist. If you're carrying something extra anyway, you might as well go big. A Crave Travel Pro 13,000mAh battery that should work nicely is on sale over at Amazon.

I don't know about you, but I always carry hammers in my pockets. So, clearly it's important I know how a smartphone will stand up to a hammer. Enter TechRax, who took it upon himself to do a hammer test on the Galaxy S5. The lesson we can all learn from this: don't hit high-density lithium-ion batteries with hammers. Just watch the very end... trust me.